How can you use balloons to show how muscles works? - Investigation instructions

'How can you use balloons to show how muscles works? - Investigation instructions' is a resource from 'What are the muscles and how do they work?', a 2nd Grade Science lesson from the unit Skeletons and Muscles. This lesson uses an enquiry-approach method, and will facilitate students answering the question 'What are the muscles and how do they work?'